Elble Rodger J, Hellriegel Helge, Raethjen Jan, Deuschl Günther
Department of Neurology Southern Illinois University School of Medicine Springfield Illinois USA.
Department of Neurology Christian-Albrechts-University Kiel Germany.
Mov Disord Clin Pract. 2016 Jul 8;4(2):205-211. doi: 10.1002/mdc3.12379. eCollection 2017 Mar-Apr.
Accelerometers and gyroscopes are used commonly in the assessment of hand tremor, but their validity in the assessment of head tremor has not been studied. We hypothesized that gyroscopy would be superior to accelerometry because head tremor is rotational motion, and gyroscopes record rotational motion, free of gravitational artifact. We also hypothesized a strong logarithmic relationship between 0 to 4-point tremor ratings and the transducer measures of tremor amplitude, similar to those previously reported for hand tremor.
Head tremor was recorded for 1 minute in each of the five head positions used in the Essential Tremor Rating Assessment Scale, using a triaxial accelerometer and triaxial gyroscope mounted at the vertex of the head. Mean and maximum 3-second burst displacement tremor and rotation tremor were computed by spectral analysis. The minimum detectable change for the transducers was estimated using the residual mean squared error from repeated-measures analysis of variance.
Tremor displacement and rotation (T) were logarithmically related to tremor ratings (tremor rating score; TRS): log(T) = α TRS + β, where α ≈ 0.47 for displacement and ≈0.64 for rotation, and β ≈ -1.8 and -1.4. Tremor ratings correlated more strongly with gyroscopy (r = 0.83-0.87) than with accelerometry (r = 0.71-0.75). Minimum detectable change (percent reduction) was approximately 66% of the baseline geometric mean.
Gyroscopic transducers are superior to accelerometry for assessment of head tremor. Both measures of head tremor are logarithmically related to tremor ratings. The minimum detectable change of the transducer measures is comparable to those previously reported for hand tremor.
加速度计和陀螺仪常用于手部震颤评估，但它们在头部震颤评估中的有效性尚未得到研究。我们假设陀螺仪在评估头部震颤方面优于加速度计，因为头部震颤是旋转运动，而陀螺仪可记录旋转运动，不受重力伪影影响。我们还假设在0至4分的震颤评分与震颤幅度的传感器测量值之间存在很强的对数关系，类似于先前报道的手部震颤情况。
使用安装在头顶的三轴加速度计和三轴陀螺仪，在特发性震颤评分评估量表中使用的五个头部位置分别记录1分钟的头部震颤。通过频谱分析计算平均和最大3秒突发位移震颤及旋转震颤。使用重复测量方差分析的残差均方误差估计传感器的最小可检测变化。
震颤位移和旋转（T）与震颤评分（震颤评分分数；TRS）呈对数关系：log(T) = α TRS + β，其中位移的α约为0.47，旋转的α约为0.64，β约为 -1.8和 -1.4。震颤评分与陀螺仪的相关性（r = 0.83 - 0.87）比与加速度计的相关性（r = 0.71 - 0.75）更强。最小可检测变化（减少百分比）约为基线几何平均值的66%。
在评估头部震颤方面，陀螺传感器优于加速度计。两种头部震颤测量方法均与震颤评分呈对数关系。传感器测量的最小可检测变化与先前报道的手部震颤相当。
